Compressively characterizing high-dimensional entangled states with complementary, random filtering

Gregory A. Howland*, Samuel H. Knarr, James Schneeloch, Daniel J. Lum, John C. Howell

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


The resources needed to conventionally characterize a quantum system are overwhelmingly large for high-dimensional systems. This obstacle may be overcome by abandoning traditional cornerstones of quantum measurement, such as general quantum states, strong projective measurement, and assumption-free characterization. Following this reasoning, we demonstrate an efficient technique for characterizing high-dimensional, spatial entanglement with one set of measurements. We recover sharp distributions with local, random filtering of the same ensemble in momentum followed by position-something the uncertainty principle forbids for projective measurements. Exploiting the expectation that entangled signals are highly correlated, we use fewer than 5000 measurements to characterize a 65,536-dimensional state. Finally, we use entropic inequalities to witness entanglement without a density matrix. Our method represents the sea change unfolding in quantum measurement, where methods influenced by the information theory and signal-processing communities replace unscalable, brute-force techniques-a progression previously followed by classical sensing.

Original languageAmerican English
Article number021018
JournalPhysical Review X
Issue number2
StatePublished - 2016
Externally publishedYes


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